Corrosion resistant aluminum electrode alloy

ABSTRACT

New aluminum alloy compositions are provided. The new aluminum alloy compositions may include, for instance, from 20 to 600 ppm Fe and from 10 to 800 ppm Mn. A ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy may be from 0.25:1 to 7:1. The new aluminum alloys may be useful, for instance, as an electrode alloy product.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent App. No. PCT/US2019/016184, filed Jan. 31, 2019, which claims the benefit of U.S. Patent Application No. 62/624,280, filed Jan. 31, 2018, each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

Broadly, the present disclosure is directed towards aluminum electrode alloys with improved corrosion resistance.

BACKGROUND

Clean, sustainable energy is a global concern. Electrochemical cells are utilized as clean, sustainable energy. By commercially deploying these sustainable forms of energy, it is possible to lower the global dependence on fossil fuels.

SUMMARY OF THE INVENTION

Utilizing aluminum alloy compositions as an aluminum electrode (e.g., anode) alloy product in an electrochemical cell can be evaluated by quantifying and/or qualifying two phenomena: (1) the anodic reaction and (2) the corrosion reaction of the aluminum electrode alloy composition. In the anodic reaction, aluminum reacts with hydroxyl ions which results in the release of electrons, the primary and desirable product of an electrochemical cell. Without being bound by any particular mechanism or theory, it is believed that in the corrosion reaction, the aluminum in the aluminum electrode (e.g., anode) alloy product material is oxidized in the presence of water and as the oxygen in the water reacts with the aluminum, aluminum oxide is formed, generating hydrogen gas (e.g. a byproduct of the corrosion reaction of the aluminum anode alloy composition). In the corrosion reaction, aluminum is consumed without contributing to the production of (creating) electrical energy in the electrochemical cell. Without being bound by a particular mechanism or theory, it is believed that by reducing the amount of corrosion reaction, more aluminum electrode alloy product material is available to participate in the anodic reaction, contributing to the longevity of the aluminum electrode alloy product and production of electrical energy by the electrochemical cell.

The extent of corrosion reaction, i.e. the amount of hydrogen generated for an aluminum electrode alloy product used as an anode, is a function of electrolyte temperatures and current densities in the electrochemical cell. As operating temperatures and applied current vary for the operation of the cell, so too does the aluminum electrode alloy composition experience varying instances of high anodic reaction and high corrosion reaction windows within the operating parameters/ranges of the electrolytic cell.

The present disclosure is directed towards aluminum alloys with improved corrosion resistance when employed as an aluminum electrode alloy product in an electrochemical cell. More specifically, the present disclosure is directed towards aluminum electrode alloys having compositions including from 20 to 600 ppm Fe (i.e., from 0.002 to 0.06 wt. % Fe), and from 10 to 800 ppm (i.e., from 0.001 to 0.08 wt. % Mn), where a ratio of Fe (ppm)-to-Mn (ppm) in the aluminum electrode alloy is from 0.25:1 to 7:1, and where aluminum is the predominant alloying element in the aluminum electrode alloy.

One or more embodiments of the present disclosure are directed towards aluminum electrode alloy compositions configured with corrosion resistant additives present in an effective amount to reduce the hydrogen generation in an electrochemical cell thereby controlling (i.e. reducing and/or eliminating) the corrosion reaction.

As used herein, the phrase “the aluminum alloy” means an alloy with aluminum as the predominant alloying element. In some embodiments, the aluminum alloy body may be selected from the group consisting of series of aluminum alloys registered with the Aluminum Association and unregistered variants of the same, as defined by the Aluminum Association document “International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” (2009). In some embodiments, the aluminum alloy is a 1xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 2xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 3xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 4xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 5xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 6xxx series aluminum alloy. In some embodiments, the aluminum alloy is a 7xxx series aluminum alloy. In some embodiments, the aluminum alloy is an 8xxx series aluminum alloy. In some embodiments, the aluminum alloy is selected from the group consisting of a 1xxx series aluminum alloy, a 2xxx series aluminum alloy, a 3xxx series aluminum alloy, a 4xxx series aluminum alloy, a 5xxx series aluminum alloy, a 6xxx series aluminum alloy, a 7xxx series aluminum alloy, and an 8xxx series aluminum alloy.

As used herein, “unavoidable impurities” in this embodiment means the presence of an undesirable component. As a non-limiting example, an unavoidable impurity is present in a quantity or amount that is low enough to not change a desired property and/or characteristic (i.e. below a threshold to modify the corrosion resistance of the corrosion resistant aluminum alloy composition and/or reduce the corrosion resistance above a certain margin of improvement when compared to the reference aluminum alloy composition material evaluated in an electrochemical cell test). Without being bound by any particular mechanism or theory, it is believed that additions of Mn as the corrosion resistant additives in an iron-containing 1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, or 8xxx series aluminum electrode alloy composition will provide improved corrosion resistance (e.g. reduced corrosion) as compared to an iron-containing aluminum alloy composition (of the same series) that does not have these Mn additions (e.g. as an alloying element).

Moreover, without being bound by any particular mechanism or theory, it is believed that additions of Mn in the aluminum electrode alloy composition (e.g. as an alloying element to an iron-containing 1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, or 8xxx series aluminum alloy) will improve corrosion resistance of the resulting aluminum anode alloy product in the electrochemical cell during a wide range of electrochemical cell operating conditions (e.g. temperature and current efficiency) as compared to an iron-containing aluminum alloy without such Mn additions. In particular, it is believed that the additions of Mn will provide significant improvement to corrosion resistance at electrochemical cell operating conditions of high corrosion (e.g. low current densities and/or low temperatures) for conventional aluminum alloy compositions without such additions.

In one aspect, an aluminum alloy composition is provided, comprising: an effective amount of a corrosion resistant additive. As used herein, an “effective amount” in this embodiment is a large enough quantity to provide an improved corrosion resistance in the aluminum electrode alloy composition (e.g. measurable, observable, and/or quantifiable). In some embodiments, improved corrosion resistance is evaluated in an electrochemical cell test. In some embodiments, the aluminum electrode alloy composition is an iron-containing 1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, or 8xxx series aluminum electrode alloy composition.

As used herein, “corrosion resistant additive” in this embodiment refers to an addition of a component to an aluminum alloy composition (e.g. 1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, or 8xxx series aluminum alloys) in order to impart corrosion resistance (e.g. reduce corrosion when evaluated as an aluminum electrode alloy product in an electrochemical cell) as compared to the alloy's corrosion without such additions.

In one aspect, the corrosion resistant additive may include Mn.

In one embodiment, aluminum is the predominant alloying element of the aluminum alloy composition.

In one embodiment, the aluminum alloy composition includes at least 90 wt. % Al.

In one embodiment, the corrosion resistant aluminum alloy composition may have: an effective amount of a corrosion resistant additive; from 20 to 600 ppm Fe; from 10-800 ppm Mn; and the balance being aluminum (e.g., and unavoidable impurities).

In some embodiments, the corrosion resistant aluminum alloy composition may have at least 1 ppm, or at least 5 ppm, or at least 10 ppm, or at least 20 ppm, or at least 30 ppm, or at least 40 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm Fe.

In some embodiments, the corrosion resistant aluminum alloy composition may have not greater than 1 ppm, or not greater than 5 ppm, or not greater than 10 ppm, or not greater than 20 ppm, or not greater than 30 ppm, or not greater than 40 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm Fe.

In some embodiments, the corrosion resistant aluminum alloy composition may have at least 1 ppm, at least 5 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm, or at least 650 ppm, or at least 700 ppm, or at least 750 ppm, or at least 800 ppm Mn, where at least some (an effective amount of) Mn is present, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum alloy composition may have from 10 to 800 ppm, or from 80 to 800 ppm, or from 70 to 800 ppm, or from 60 to 800 ppm, or from 50 to 800 ppm, or from 40 to 800 ppm, or from 30 to 600 ppm, or from 28 to 560 ppm, or from 26 to 520 ppm, or from 24 to 480 ppm, or from 22 to 440 ppm, or from 20 to 400 ppm, or from 18 to 360 ppm, or from 16 to 320 ppm, or from 14 to 280 ppm, or from 12 to 240 ppm, or from 10 to 200 ppm, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum alloy composition may have about 10 ppm, or about 15 ppm, or about 20 ppm, or about 50 ppm, or about 60 ppm, or about 70 ppm, or about 80 ppm, or about 100 ppm, or about 150 ppm, or about 200 ppm, or about 250 ppm, or about 300 ppm, or about 350 ppm, or about 400 ppm, or about 450 ppm, or about 500 ppm, or about 550 ppm, or about 600 ppm, or about 650 ppm, or about 700 ppm, or about 750 ppm, or about 800 ppm, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum alloy composition may have 10 ppm, or 15 ppm, or 20 ppm, or 50 ppm, or 60 ppm, or 70 ppm, or 80 ppm, or 100 ppm, or 150 ppm, or 200 ppm, or 250 ppm, or 300 ppm, or 350 ppm, or 400 ppm, or 450 ppm, or 500 ppm, or 550 ppm, or 600 ppm, or 650 ppm, or 700 ppm, or 750 ppm, or 800 ppm, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum alloy composition may contain an effective amount of the corrosion resistant additive, Mn. In some embodiments, the effective amount of the corrosion resistant additive, Mn, may include any of the manganese amounts described above, e.g. from 10 to 800 ppm Mn. In some embodiments, the corrosion resistant aluminum alloy composition may contain, as a purposefully added alloying element, Mn in any of the amounts described above, e.g. from 10 to 800 ppm Mn, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum alloy composition may be any suitable aluminum alloy, such as any of the 1xxx series, 2xxx series, 3xxx series, 4xxx series, 5xxx series, 6xxx series, 7xxx series, or 8xxx series aluminum alloy compositions described above, and the corrosions resistant aluminum alloy composition may include any of the manganese amounts described above, e.g. an effective amount of Mn as corrosion resistant additive; from 20 to 600 ppm Fe; from 10-800 ppm Mn; and the balance being aluminum (e.g., and unavoidable impurities).

In one embodiment, the corrosion resistant aluminum alloy composition may include at least 0.005 vol. % of Fe—Mn-bearing intermetallic particles, where a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy is from 0.25:1 to 7:1.

In one embodiment, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum alloy composition may be from about 0.25:1 to about 7:1. In one embodiment, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum alloy composition may be 1.0. In another embodiment, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum alloy composition may be about 1.0. In some embodiments, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum alloy composition may be at least 0.25, or at least 0.35, or at least 0.45, or least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9, or at least 1.0. In some embodiments, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum alloy composition may be not greater than 7.0, or not greater than 6.5, or not greater than 6.0, or not greater than 5.5, or not greater than 5.0, or not greater than 4.5, or not greater than 4.0, or not greater than 3.5, or not greater than 3.0, or not greater than 2.5, or not greater than 2.0, or not greater than 1.5, or not greater than 1.0.

In one embodiment, the corrosion resistant aluminum alloy composition may include not greater than 0.04 vol. % of Fe—Mn-bearing intermetallic particles.

In some embodiments, in addition to the corrosion resistant additive manganese, an effective amount of other optional corrosion resistant additives may be added. Optional corrosion resistant additives may include, for instance, zinc and/or gallium. Examples of zinc and/or gallium as corrosion resistant additives are defined and described in commonly-owned International Patent Application No. PCT/US2017/066053, entitled, “Corrosion Resistant Aluminum Alloy,” filed Dec. 13, 2017, published as WO2018/112018. As described herein, “optional corrosion resistant additive” refers to an optional addition of a component to an aluminum alloy composition in order to impart corrosion resistance as compared to the alloy's corrosion without such additions. The optional corrosion resistant additive may be added in addition to manganese. Various embodiments relating to optional corrosion resistant additives are described herein.

In one embodiment, an optional corrosion resistant additive may be Zn. In another embodiment, an optional corrosion resistant additive may be Ga. In yet another embodiment, optional corrosion resistant additives may be Zn and Ga. In another embodiment, optional corrosion resistant additives are selected from the group consisting of: Zn, Ga, and combinations thereof.

In some embodiments, the effective amount of optional corrosion resistant additive may be at least 5 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm, or at least 650 ppm, or at least 700 ppm, or at least 750 ppm, or at least 800 ppm, or at least 850 ppm, or at least 900 ppm, or at least 950 ppm, or at least 1000 ppm, where at least some (an effective amount of) Zn and Ga are present, when both Zn and Ga are utilized as the optional corrosion resistant additives.

In some embodiments, the effective amount of optional corrosion resistant additive may be not greater than 5 ppm, or not greater than 10 ppm, or not greater than 15 ppm, or not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm, or not greater than 650 ppm, or not greater than 700 ppm, or not greater than 750 ppm, or not greater than 800 ppm, or not greater than 850 ppm, or not greater than 900 ppm, or not greater than 950 ppm, or not greater than 1000 ppm, where not greater than some (an effective amount of) Zn and Ga are present, when both Zn and Ga are utilized as the optional corrosion resistant additives.

In one or more of the aforementioned embodiments, the amount of Zn as an optional corrosion resistant additive as an individual addition may be not greater than 500 ppm of the corrosion resistant aluminum alloy composition. In some embodiments, the effective amount of optional corrosion resistant additive of Zn may be at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm. In some embodiments, the effective amount of optional corrosion resistant additive of Zn may be not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm. In some embodiments, an effective amount of the optional corrosion resistant additive of Zn may be at least 20 ppm to not greater than 500 ppm.

In one or more of the aforementioned embodiments, the amount of Ga as an optional corrosion resistant additive as an individual addition may be not greater than 600 ppm of the corrosion resistant aluminum alloy composition. In one or more of the aforementioned embodiments, the amount of Ga as an optional corrosion resistant additive as an individual addition may be not greater than 0.0 ppm of the corrosion resistant aluminum alloy composition. In some embodiments, the effective amount of an optional corrosion resistant additive of Ga may be at least 5 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm. In some embodiments, the effective amount of an optional corrosion resistant additive of Ga may be not greater than 5 ppm, or not greater than 10 ppm, or not greater than 15 ppm, or not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm. In some embodiments, the effective amount of an optional corrosion resistant additive of Ga may be at least 20 ppm to not greater than 500 ppm.

In some embodiments, an effective amount of the optional corrosion resistant additive may be at least 5 ppm to not greater than 600 ppm, or at least 10 ppm to not greater than 300 ppm, or at least 5 ppm to not greater than 100 ppm, or at least 5 ppm to not greater than 50 ppm, or at least 20 ppm to not greater than 100 ppm, or at least 20 ppm to not greater than 50 ppm, or at least 20 ppm to not greater than 1000 ppm, or at least 50 ppm to not greater than 1000 ppm, or at least 50 ppm to not greater than 700 ppm, or at least 50 ppm to not greater than 500 ppm, or at least 50 ppm to not greater than 300 ppm, or at least 50 ppm to not greater than 200 ppm, or at least 50 ppm to not greater than 100 ppm, or at least 20 ppm to not greater than 500 ppm of each additive, where the total amount of the optional corrosion resistant additive is not greater than 1000 ppm.

In some embodiments, an effective amount of optional corrosion resistant additive may be not greater than 1000 ppm, or not greater than 500 ppm, or not greater than 250 ppm, or not greater than 100 ppm, or not greater than 50 ppm, or not greater than 20 ppm, where at least some optional corrosion resistant additive is present

In any of the foregoing embodiments, the optional corrosion resistant additive may be Zn and Ga in equal amounts. In any of the foregoing embodiments, the optional corrosion resistant additive may be Zn and Ga, with a greater amount of Zn than Ga. In any of the foregoing embodiments, the optional corrosion resistant additive may be Zn and Ga, with a lesser amount of Zn than Ga.

As noted above, the corrosion resistant aluminum alloy composition may be a 5xxx series alloy. In some embodiments, the corrosion resistant aluminum alloy composition may include at least 0.2 wt. % Mg, or at least 0.5 wt. %, or at least 1.0 wt. %, or at least 1.5 wt. %, or at least 2.0 wt. % Mg. In some embodiments, the corrosion resistant aluminum alloy composition may include not greater than 5.0 wt. %, or not greater than 4.0 wt. %, or not greater than 3.0 wt. %, or not greater than 2.0 wt. % Mg, or not greater than 1.5 wt. %, or not greater than 1.0 wt. %, or not greater than 0.5 wt. % Mg. In some embodiments, the corrosion resistant aluminum alloy composition may include from 0.2 to 5.0 wt. %, or from 0.5 to 5.0 wt. %, or from 1.0 to 5.0 wt. %, or from 1.5 to 5.0 wt. %, or from 2.0 to 5.0 wt. %, or from 3.0 to 5.0 wt. %, or from 4.0 to 5.0 wt. %, or from 0.01 to 4.0 wt. %, or from 0.2 to 3.0 wt. %, or from 0.2 to 2.0 wt. %, or from 0.2 to 1.5 wt. %, or from 0.2 to 1.0 wt. % Mg. In one embodiment, the corrosion resistant aluminum alloy composition has no Mg (i.e. includes Mg as an impurity only).

In one approach, the corrosion resistant aluminum alloy composition may be a 5xxx series alloy and may include 0.2-5.0 wt. % Mg, 20-600 ppm Fe, 10-800 ppm Mn, where a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy is from 0.25:1 to 7:1. In one embodiment, the corrosion resistant 5xxx aluminum alloy may include 70-110 ppm Fe, 30-50 ppm Mn, where a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy is from 1.4:1 to 3.6:1, 90-110 ppm Zn, and 90-110 ppm Ga. In one embodiment, the corrosion resistant 5xxx aluminum alloy may include from 0.005 to 0.04 vol. % of Fe—Mn-bearing intermetallic particles.

Some non-limiting embodiments of various corrosion resistant aluminum alloy compositions are provided in Table 1, below.

TABLE 1 Mg Fe Mn Zn Ga Alloy (wt. %) (ppm) (ppm) Fe:Mn ratio (ppm) (ppm) A 0.2-5.0 20-600  10-800 0.03:1-60:1  ≤500 ≤500 B 0.3-4.5 20-500  10-700 0.05:1-50:1  ≤450 ≤450 C 0.4-4.5 30-500  20-600 0.06:1-25:1  ≤400 ≤400 D 0.5-4.5 30-450  20-500 0.08:1-23:1  ≤350 ≤350 E 0.5-4.0 30-400  20-400 0.13:1-20:1  ≤325 ≤325 F 0.75-4.0  40-350  20-300 0.16:1-17.5:1 ≤300 ≤300 G 0.75-3.5  40-300  20-250 0.2:1-15:1 10-275 10-275 H 1.0-3.5 40-250  20-200  0.3:1-12.5:1 20-250 20-250 I 1.0-3.0 50-200  30-150 0.5:1-6.7:1 30-225 30-225 J 1.5-3.0 50-150  30-100 0.8:1-5:1  40-200 40-200 K 2.0-3.0 60-130 30-75 1.4:1-4.3:1 50-150 50-150 L 2.3-2.7 70-110 30-50 1.4:1-3.6:1 90-110 90-110

The embodiments listed in Table 1, above, may also be used in the corrosion resistant aluminum electrode alloys described herein.

As used herein, “reference aluminum alloy composition” in this embodiment means an aluminum alloy composition having less than 3 ppm Mn.

As used herein, “reference aluminum electrode alloy product” in this embodiment means an aluminum electrode (e.g., anode) alloy product formed from the reference aluminum alloy composition.

In one or more of the aforementioned embodiments, the iron-containing corrosion resistant aluminum alloy composition may be configured with the corrosion resistant additive(s) (e.g., Mn) in an effective amount such, when employed as an aluminum electrode (e.g., anode) alloy product, the aluminum alloy composition has a greater corrosion resistance as compared to an a reference aluminum electrode (e.g., anode) alloy product formed from an iron-containing reference (e.g., baseline/control) aluminum alloy composition without such Mn additives, when measured in accordance with an electrochemical cell test.

In one embodiment, the reference aluminum alloy composition may contain a substantially equivalent amount of Fe as a sample (non-baseline/control) aluminum electrode alloy composition.

In another aspect, an aluminum electrode alloy is provided, comprising: an effective amount of a corrosion resistant additive. As used herein, an “effective amount” in this embodiment is a large enough quantity to provide an improved corrosion resistance in the aluminum electrode alloy composition (e.g. measurable, observable, and/or quantifiable). In some embodiments, improved corrosion resistance is evaluated in an electrochemical cell test. In some embodiments, the aluminum electrode alloy composition is an iron-containing 1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, or 8xxx series aluminum electrode alloy composition.

As used herein, “corrosion resistant additive” in this embodiment refers to an addition of a component to an aluminum electrode alloy (e.g. 1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, 7xxx, or 8xxx series aluminum alloys) in order to impart corrosion resistance (e.g. reduce corrosion when evaluated as an aluminum electrode alloy product in an electrochemical cell) as compared to the alloy's corrosion without such additions.

In one embodiment, the corrosion resistant additive may include Mn.

In one embodiment, aluminum is the predominant alloying element of the aluminum electrode alloy.

In one embodiment, the aluminum electrode alloy includes at least 90 wt. % Al.

In one embodiment, the corrosion resistant aluminum electrode alloy has: an effective amount of a corrosion resistant additive; from 20 to 600 ppm Fe; from 10-800 ppm Mn; and the balance being aluminum (e.g., and unavoidable impurities).

In some embodiments, the corrosion resistant aluminum electrode alloy may have at least 1 ppm, or at least 5 ppm, or at least 10 ppm, or at least 20 ppm, or at least 30 ppm, or at least 40 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm Fe.

In some embodiments, the corrosion resistant aluminum electrode alloy may have not greater than 1 ppm, or not greater than 5 ppm, or not greater than 10 ppm, or not greater than 20 ppm, or not greater than 30 ppm, or not greater than 40 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm Fe.

In some embodiments, the corrosion resistant aluminum electrode alloy may have at least 1 ppm, at least 5 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm, or at least 650 ppm, or at least 700 ppm, or at least 750 ppm, or at least 800 ppm Mn, where at least some (an effective amount of) Mn is present, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum electrode alloy may have not greater than 1 ppm, or not greater than 5 ppm, or not greater than 10 ppm, or not greater than 15 ppm, or not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm, or not greater than 650 ppm, or not greater than 700 ppm, or not greater than 750 ppm, or not greater than 800 ppm Mn, where not greater than some (an effective amount of) Mn is present, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum electrode alloy may have from 10 to 800 ppm, or from 80 to 800 ppm, or from 70 to 800 ppm, or from 60 to 800 ppm, or from 50 to 800 ppm, or from 40 to 800 ppm, or from 30 to 600 ppm, or from 28 to 560 ppm, or from 26 to 520 ppm, or from 24 to 480 ppm, or from 22 to 440 ppm, or from 20 to 400 ppm, or from 18 to 360 ppm, or from 16 to 320 ppm, or from 14 to 280 ppm, or from 12 to 240 ppm, or from 10 to 200 ppm, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum electrode alloy may have about 10 ppm, or about 15 ppm, or about 20 ppm, or about 50 ppm, or about 60 ppm, or about 70 ppm, or about 80 ppm, or about 100 ppm, or about 150 ppm, or about 200 ppm, or about 250 ppm, or about 300 ppm, or about 350 ppm, or about 400 ppm, or about 450 ppm, or about 500 ppm, or about 550 ppm, or about 600 ppm, or about 650 ppm, or about 700 ppm, or about 750 ppm, or about 800 ppm, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum electrode alloy may have 10 ppm, or 15 ppm, or 20 ppm, or 50 ppm, or 60 ppm, or 70 ppm, or 80 ppm, or 100 ppm, or 150 ppm, or 200 ppm, or 250 ppm, or 300 ppm, or 350 ppm, or 400 ppm, or 450 ppm, or 500 ppm, or 550 ppm, or 600 ppm, or 650 ppm, or 700 ppm, or 750 ppm, or 800 ppm, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum electrode alloy may contain an effective amount of the corrosion resistant additive, Mn. In some embodiments, the effective amount of the corrosion resistant additive, Mn, may include any of the manganese amounts described above, e.g. from 10 to 800 ppm Mn. In some embodiments, the corrosion resistant aluminum electrode alloy may contain, as a purposefully added alloying element, Mn in any of the amounts described above, e.g. from 10 to 800 ppm Mn, when Mn is utilized as the corrosion resistant additive.

In some embodiments, the corrosion resistant aluminum electrode alloy may be any suitable aluminum alloy, such as any of the 1xxx series, 2xxx series, 3xxx series, 4xxx series, 5xxx series, 6xxx series, 7xxx series, or 8xxx series aluminum alloy compositions described above, and the corrosion resistant aluminum electrode alloy may include any of the Mn amounts described above, e.g. an effective amount of Mn as a corrosion resistant additive; from 20 to 600 ppm Fe; from 10-800 ppm Mn; and the balance being aluminum (e.g., and unavoidable impurities).

In one embodiment, the corrosion resistant aluminum electrode alloy may include at least 0.005 vol. % of Fe—Mn-bearing intermetallic particles, where a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy is from 0.25:1 to 7:1.

In one embodiment, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy may be from about 0.25:1 to about 7:1. In one embodiment, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy may be 1.0. In another embodiment, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy may be about 1.0. In some embodiments, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum electrode alloy may be at least 0.25, or at least 0.35, or at least 0.45, or at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9, or at least 1.0. In some embodiments, a ratio of Fe (ppm)-to-Mn (ppm) in the corrosion resistant aluminum alloy composition may be: not greater than 7.0, or not greater than 6.5, or not greater than 6.0, or not greater than 5.5, or not greater than 5.0, or not greater than 4.5, or not greater than 4.0, or not greater than 3.5, or not greater than 3.0, or not greater than 2.5, or not greater than 2.0, or not greater than 1.5, or not greater than 1.0.

In one embodiment, the corrosion resistant aluminum electrode alloy may include not greater than 0.04 vol. % of Fe—Mn-bearing intermetallic particles.

As used herein, “reference aluminum electrode alloy” in this embodiment means an aluminum alloy having less than 3 ppm Mn.

In some embodiments, in addition to the corrosion resistant additive manganese, an effective amount of other optional corrosion resistant additives may be added. Optional corrosion resistant additives may include, for instance, zinc and/or gallium. Examples of zinc and/or gallium as corrosion resistant additives are defined and described in commonly-owned International Patent Application No. PCT/US2017/066053, entitled, “Corrosion Resistant Aluminum Alloy,” filed Dec. 13, 2017, published as WO2018/112018. As described herein, “optional corrosion resistant additive” refers to an optional addition of a component to an aluminum electrode alloy in order to impart corrosion resistance as compared to the alloy's corrosion without such additions. The optional corrosion resistant additive may be added in addition to manganese. Various embodiments relating to optional corrosion resistant additives are described herein.

In one embodiment, an optional corrosion resistant additive may be Zn. In another embodiment, an optional corrosion resistant additive may be Ga. In yet another embodiment, optional corrosion resistant additives may be Zn and Ga. In another embodiment, optional corrosion resistant additives are selected from the group consisting of: Zn, Ga, and combinations thereof.

In some embodiments, the effective amount of optional corrosion resistant additive may be at least 5 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm, or at least 650 ppm, or at least 700 ppm, or at least 750 ppm, or at least 800 ppm, or at least 850 ppm, or at least 900 ppm, or at least 950 ppm, or at least 1000 ppm, where at least some (an effective amount of) Zn and Ga are present, when both Zn and Ga are utilized as the optional corrosion resistant additives.

In some embodiments, the effective amount of optional corrosion resistant additive may be not greater than 5 ppm, or not greater than 10 ppm, or not greater than 15 ppm, or not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm, or not greater than 650 ppm, or not greater than 700 ppm, or not greater than 750 ppm, or not greater than 800 ppm, or not greater than 850 ppm, or not greater than 900 ppm, or not greater than 950 ppm, or not greater than 1000 ppm, where not greater than some (an effective amount of) Zn and Ga are present, when both Zn and Ga are utilized as the optional corrosion resistant additives.

In one or more of the aforementioned embodiments, the amount of Zn as an optional corrosion resistant additive as an individual addition may be not greater than 500 ppm of the corrosion resistant aluminum electrode alloy. In some embodiments, the effective amount of optional corrosion resistant additive of Zn may be at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm. In some embodiments, the effective amount of optional corrosion resistant additive of Zn may be not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm. In some embodiments, an effective amount of the optional corrosion resistant additive of Zn may be at least 20 ppm to not greater than 500 ppm.

In one or more of the aforementioned embodiments, the amount of Ga as an optional corrosion resistant additive as an individual addition may be: not greater than 600 ppm of the corrosion resistant aluminum electrode alloy. In one or more of the aforementioned embodiments, the amount of Ga as an optional corrosion resistant additive as an individual addition may be not greater than 0.0 ppm of the corrosion resistant aluminum electrode alloy. In some embodiments, the effective amount of an optional corrosion resistant additive of Ga may be at least 5 ppm, or at least 10 ppm, or at least 15 ppm, or at least 20 ppm, or at least 50 ppm, or at least 100 ppm, or at least 150 ppm, or at least 200 ppm, or at least 250 ppm, or at least 300 ppm, or at least 350 ppm, or at least 400 ppm, or at least 450 ppm, or at least 500 ppm, or at least 550 ppm, or at least 600 ppm. In some embodiments, the effective amount of an optional corrosion resistant additive of Ga may be not greater than 5 ppm, or not greater than 10 ppm, or not greater than 15 ppm, or not greater than 20 ppm, or not greater than 50 ppm, or not greater than 100 ppm, or not greater than 150 ppm, or not greater than 200 ppm, or not greater than 250 ppm, or not greater than 300 ppm, or not greater than 350 ppm, or not greater than 400 ppm, or not greater than 450 ppm, or not greater than 500 ppm, or not greater than 550 ppm, or not greater than 600 ppm. In some embodiments, the effective amount of an optional corrosion resistant additive of Ga may be at least 20 ppm to not greater than 500 ppm.

In some embodiments, an effective amount of the optional corrosion resistant additive may be at least 5 ppm to not greater than 600 ppm, or at least 10 ppm to not greater than 300 ppm, or at least 5 ppm to not greater than 100 ppm, or at least 5 ppm to not greater than 50 ppm, or at least 20 ppm to not greater than 100 ppm, or at least 20 ppm to not greater than 50 ppm, or at least 20 ppm to not greater than 1000 ppm, or at least 50 ppm to not greater than 1000 ppm, or at least 50 ppm to not greater than 700 ppm, or at least 50 ppm to not greater than 500 ppm, or at least 50 ppm to not greater than 300 ppm, or at least 50 ppm to not greater than 200 ppm, or at least 50 ppm to not greater than 100 ppm, or at least 20 ppm to not greater than 500 ppm of each additive, where the total amount of the optional corrosion resistant additive is not greater than 1000 ppm.

In some embodiments, an effective amount of optional corrosion resistant additive may be not greater than 1000 ppm, or not greater than 500 ppm, or not greater than 250 ppm, or not greater than 100 ppm, not greater than 50 ppm, or not greater than 20 ppm, where at least some optional corrosion resistant additive is present.

In any of the foregoing embodiments, the optional corrosion resistant additive may be Zn and Ga in equal amounts. In any of the foregoing embodiments, the optional corrosion resistant additive may be Zn and Ga, with a greater amount of Zn than Ga. In any of the foregoing embodiments, the optional corrosion resistant additive may be Zn and Ga, with a lesser amount of Zn than Ga.

As noted above, the corrosion resistant aluminum electrode alloy may be a 5xxx series alloy. In some embodiments, the corrosion resistant aluminum alloy composition may include at least 0.2 wt. % Mg, or at least 0.5 wt. %, or at least 1.0 wt. %, or at least 1.5 wt. %, or at least 2.0 wt. % Mg. In some embodiments, the corrosion resistant aluminum electrode alloy may include not greater than 5.0 wt. %, or not greater than 4.0 wt. %, or not greater than 3.0 wt. %, or not greater than 2.0 wt. % Mg, or not greater than 1.5 wt. %, or not greater than 1.0 wt. %, or not greater than 0.5 wt. % Mg. In some embodiments, the corrosion resistant aluminum electrode alloy may include from 0.2 to 5.0 wt. %, or from 0.5 to 5.0 wt. %, or from 1.0 to 5.0 wt. %, or from 1.5 to 5.0 wt. %, or from 2.0 to 5.0 wt. %, or from 3.0 to 5.0 wt. %, or from 4.0 to 5.0 wt. %, or from 0.2 to 4.0 wt. %, or from 0.2 to 3.0 wt. %, or from 0.2 to 2.0 wt. %, or from 0.2 to 1.5 wt. %, or from 0.2 to 1.0 wt. % Mg. In one embodiment, the corrosion resistant aluminum electrode alloy has no Mg (i.e. includes Mg as an impurity only).

As used herein, “reference aluminum electrode alloy product” in this embodiment means an aluminum electrode (e.g., anode) alloy product formed from the reference aluminum electrode alloy.

In one or more of the aforementioned embodiments, the iron-containing corrosion resistant aluminum electrode alloy may be configured with the corrosion resistant additive(s) (e.g., Mn) in an effective amount such, when employed as an aluminum electrode (e.g., anode) alloy product, the aluminum electrode alloy may have a greater corrosion resistance as compared to an a reference aluminum electrode (e.g., anode) alloy product formed from an iron-containing reference (e.g., baseline/control) aluminum electrode alloy without such Mn additives, when measured in accordance with an electrochemical cell test.

In one embodiment, the reference aluminum electrode alloy may contain a substantially equivalent amount of Fe as a sample (non-baseline/control) aluminum electrode alloy.

In yet another aspect embodiment, a method for producing an aluminum electrode alloy product may comprise the steps of: a) forming a melt of an aluminum alloy, and (b) depositing the melt to form an aluminum electrode alloy product. The forming step a) may comprise (i) using 20-600 ppm Fe in the melt, and (ii) using 10-800 ppm Mn in the melt, where a ratio of Fe (ppm)-to-Mn (ppm) in the melt is from 0.5:1 to 4:1, and where aluminum is the predominant alloying element of the aluminum alloy product. The depositing step b) may comprise (i) casting the melt into the aluminum electrode alloy product, and (ii) producing at least 0.005 vol. % of Fe—Mn-bearing intermetallic particles, where the aluminum electrode alloy product includes at least 0.005 vol. % of the Fe—Mn-bearing intermetallic particles.

In some embodiments, the improved corrosion resistance of various embodiments of the aforementioned aluminum electrode alloys was demonstrated in the electrochemical cell presented in FIG. 1. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention. Further, some features may be exaggerated to show details of particular components.

Aspects of the invention will now be described with reference to the following numbered clauses:

1. An aluminum alloy composition comprising:

-   -   a) 20-600 ppm Fe;     -   b) 10-800 ppm Mn; and     -   c) at least 0.005 vol. % of Fe—Mn-bearing intermetallic         particles, wherein:         -   (i) a ratio of Fe (ppm)-to-Mn (ppm) in the aluminum             composition alloy is from 0.25:1 to 7:1.

2. The aluminum alloy composition of clause 1, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is at least 0.5.

3. The aluminum alloy composition of clause 2, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is at least 0.7.

4. The aluminum alloy composition of clause 3, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is at least 0.9.

5. The aluminum alloys composition of clause 4, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is not greater than 5.0.

6. The aluminum alloy composition of clause 5, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is not greater than 3.0.

7. The aluminum alloy composition of clause 6, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is not greater than 1.5.

8. The aluminum alloy composition of clause 1 comprising not greater than 0.04 vol. % of the Fe—Mn-bearing intermetallic particles.

9. The aluminum alloy composition of any of the preceding clauses, wherein the aluminum alloy composition comprises an optional corrosion resistant additive, wherein the optional corrosion resistant additive is selected from the group consisting of Zn, Ga, and combinations thereof.

10. The aluminum alloy composition of clause 9, wherein the optional corrosion resistant additive comprises from 20 ppm to 1000 ppm of optional corrosion resistant additive.

11. The aluminum alloy composition of any of clauses 9-10, wherein the optional corrosion resistant additive comprises from 20 ppm to 500 ppm Zn.

12. The aluminum alloy composition of any of clauses 9-11, wherein the optional corrosion resistant additive comprises from 20 ppm to 500 ppm Ga.

13. The aluminum alloy composition of any of the preceding clauses, wherein the aluminum alloy composition is suitable for use as an aluminum electrode alloy.

14. The aluminum alloy composition of clause 13, wherein, when measured in accordance with an electrochemical cell test, a corrosion resistance of the aluminum electrode alloy is greater as compared to a corrosion resistance of a reference aluminum electrode alloy.

15. A method comprising:

-   -   a) forming a melt of an aluminum alloy composition, the forming         comprising:         -   (i) using 20-600 ppm Fe in the melt; and         -   (ii) using 10-800 ppm Mn in the melt, wherein:             -   (I) a ratio of Fe (ppm)-to-Mn (ppm) in the melt is from                 0.25:1 to 7:1; and     -   b) depositing the melt to form an aluminum electrode alloy         product, wherein the depositing comprises:         -   (i) casting the melt into the aluminum electrode alloy             product; and         -   (ii) producing at least 0.005 vol. % of Fe—Mn-bearing             intermetallic particles,     -   wherein the aluminum electrode alloy product includes the at         least 0.005 vol. % of the Fe—Mn-bearing intermetallic particles.

16. The method of clause 15, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is at least 0.5.

17. The method of clause 16, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is at least 0.7.

18. The method of clause 17, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is at least 0.9.

19. The method of clause 18, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is not greater than 5.0.

20. The method of clause 19, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is not greater than 3.0.

21. The method of clause 20, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is not greater than 1.5.

22. The method of clause 15, wherein the aluminum electrode alloy product includes not greater than 0.04 vol. % of the Fe—Mn-bearing intermetallic particles.

23. The method of any of clauses 15-22, wherein the forming step (a) comprises using an optional corrosion resistant additive in the melt, wherein the optional corrosion resistant additive is selected from the group consisting of Zn, Ga, and combinations thereof.

24. The method of clause 23, wherein the optional corrosion resistant additive comprises from 20 ppm to 1000 ppm of optional corrosion resistant additive.

25. The method of any of clauses 23-24, wherein the optional corrosion resistant additive comprises from 20 ppm to 500 ppm Zn.

26. The method of any of clauses 23-25, wherein the optional corrosion resistant additive comprises from 20 ppm to 500 ppm Ga.

27. The method of any of clauses 15-26, wherein, when measured in accordance with an electrochemical cell test, a corrosion resistance of the aluminum electrode alloy product cast from the melt is greater as compared to the corrosion resistance of a reference aluminum electrode alloy product produced using a reference aluminum electrode alloy.

28. A 5xxx aluminum alloy composition comprising:

-   -   a) 0.2-5.0 wt. % Mg;     -   b) 20-600 ppm Fe; and     -   c) 10-800 ppm Mn, wherein a ratio of Fe (ppm)-to-Mn (ppm) in the         aluminum composition alloy is from 0.25:1 to 7:1.

29. The 5xxx aluminum alloy composition of clause 28, wherein the aluminum alloy composition includes 70-110 ppm Fe, 30-50 ppm Mn, wherein a ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is from 1.4:1 to 3.6:1, 90-110 ppm Zn, and 90-110 ppm Ga.

30. The 5xxx aluminum alloy composition of clause 29, wherein the 5xxx aluminum alloy comprises from 0.005 to 0.04 vol. % of Fe—Mn-bearing intermetallic particles.

The figures constitute a part of this specification and include illustrative embodiments of the present disclosure and illustrate various objects and features thereof. In addition, any measurements, specifications and the like shown in the figures are intended to be illustrative, and not restrictive. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

Among those benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments of the invention is intended to be illustrative, and not restrictive.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases “in one embodiment” and “in some embodiments” as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention.

In addition, as used herein, the term “or” is an inclusive “or” operator, and is equivalent to the term “and/or,” unless the context clearly dictates otherwise. The term “based on” is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of “a,” “an,” and “the” include plural references. The meaning of “in” includes “in” and “on”.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example of an electrochemical cell that is configured for use in evaluating the corrosion of electrodes in an electrolyte in accordance with Example 2.

FIG. 2 is a graph showing hydrogen gas generation for different aluminum electrode alloy compositions in accordance with Examples 1 and 2.

DETAILED DESCRIPTION Examples

The following examples are intended to illustrate the invention and should not be construed as limiting the invention in any way.

Example 1—Preparing Aluminum Electrode Alloy Product Samples

Aluminum electrode alloys, having the compositions shown in Table 2, below, were cast as ingots. The target magnesium content for all alloys was 2.5 wt. %. The target iron content for all alloys was 90 ppm. The A-alloys had varying amounts of manganese, but contained no gallium or zinc. The B-alloys had varying amounts of manganese and also contained gallium and zinc.

TABLE 2 Composition of Ex. 1 Alloys Hydrogen Alloy Mg Fe Mn Ga Zn Generation no. (w %) (ppm) (ppm) (ppm) (ppm) (L) 1-A 2.62 90 0 0 0 2.321 2-A 2.57 80 40 0 0 2.669 3-A 2.54 90 90 0 0 2.227 4-A 2.54 80 280 0 0 2.305 5-A 2.54 80 580 0 0 2.181 6-A 2.53 90 1960 0 0 2.448 1-B 2.49 94 0 104 110 3.120 2-B 2.49 98 43 100 110 1.504 3-B 2.57 102 92 100 100 1.960 4-B 2.53 101 180 100 110 1.805 5-B 2.52 98 520 100 100 2.439 6-B 2.55 98 2000 100 100 5.110

The ingots were then rolled to the desired thickness, and machined into disks having a desired thickness and a diameter, with a sufficient cross-sectional surface area to provide a viable testing surface for immersion into an electrochemical cell (schematically depicted in FIG. 1) for the evaluation and assessment of corrosion within the range of operating conditions of the cell (e.g. time, temperatures, current efficiency, etc.).

Example 2—Testing the Aluminum Electrode Alloy Product Samples

All alloys were tested for corrosion resistance (e.g. hydrogen generation) via an electrochemical cell system (schematically depicted in FIG. 1). The electrochemical cell consists of a counter electrode and an aluminum electrode (anode) alloy product submerged in an aqueous electrolyte. The electrochemical cell is equipped with a mass-flow meter for measuring hydrogen gas evolved from the aluminum anode alloy product. Current is applied on the aluminum anode alloy product, through the electrolyte, into the counter electrode.

The alloys were tested according to the following procedure. A predefined temperature-and-current step control program was applied to the cell so that the hydrogen evolution rate was measured over a set range of operating temperatures, i.e. between room temperature and 100° C. and over a set of current densities, ranging from 0 to 300 mA/cm².

The alloys were run under identical conditions including electrolyte temperature, applied current, and test duration. Results are generated based on hydrogen generation, by accumulating the overall amount of hydrogen measured by the mass flow meter. Without being bound by a particular mechanism theory, it is believed that the overall amount of hydrogen generated by the system corresponds to the corrosion reaction (undesired reaction). Thus, the less hydrogen produced, the more corrosion resistant the aluminum anode alloy is that is being evaluated.

FIG. 2 shows the hydrogen generation results for all alloys. The results of the A-alloys show the effects of adding manganese to the alloy. Alloy 1-A contains no manganese to serve as a control. Alloys 3-A, 4-A, and 5-A generated less hydrogen than alloy 1-A, demonstrating a beneficial effect of manganese on corrosion resistance at some amounts. Both alloys 2-A and 6-A generated more hydrogen than alloy 1-A, indicating there may be a beneficial range of manganese addition. Regarding the B-alloys, all of the B Alloys contained the same amount of gallium and zinc, and the manganese content was varied in a similar manner to the A-alloys. As shown in FIG. 2, alloys 2-B, 3-B and 4-B all generated less hydrogen than the corresponding A-alloys. Additionally, these three B-alloys all generated less hydrogen than both alloys 1-A and 1-B, indicating the beneficial effect of manganese, gallium and zinc on hydrogen generation. Alloy 5-B generated more hydrogen than alloy 5-A, and alloy 6-B generated the most hydrogen of all samples, indicating that there may be a beneficial range of concentrations of manganese, gallium and zinc for hydrogen generation.

Without being bound to any particular mechanism or theory, it is believed that in iron-containing aluminum electrode (e.g., anode) alloy products (e.g., having 70 ppm Fe), the hydrogen gas generation observed in the electrochemical cell test occurs primarily at Fe-bearing phases and/or particles present in the material. For aluminum electrode anode products containing iron (e.g., having greater than about 60 ppm Fe), but without manganese as a purposeful alloying addition (e.g., alloys 1-A and 1-B), it is believed that the corrosion reaction in the electrochemical cell test proceeds at a faster rate as compared to, for instance, alloys 3-A and 3-B, due to a comparatively higher electrochemical difference between Fe-bearing phases and the aluminum alloy matrix. As such, alloys 1-A and 1-B were prone to greater material degradation and a lower electrical energy generation performance as compared other samples that contained manganese.

Without being bound to any particular mechanism or theory, it is believed that the Mn additives to the aluminum anode alloy products facilitate sequestration of at least a portion of the iron, thereby forming Fe—Mn-bearing intermetallic particles, and so reducing the electrochemical difference between the Fe-bearing phases and the aluminum alloy matrix.

While a number of embodiments of the present invention have been described, it is understood that these embodiments are illustrative only, and not restrictive, and that many modifications may become apparent to those of ordinary skill in the art. Further still, the various steps may be carried out in any desired order (and any desired steps may be added and/or any desired steps may be eliminated). 

What is claimed is:
 1. An aluminum alloy comprising: a) 20-600 ppm Fe; b) 10-800 ppm Mn; and c) at least 0.005 vol. % of Fe—Mn-bearing intermetallic particles, wherein: (i) a ratio of Fe (ppm)-to-Mn (ppm) in the aluminum composition alloy is from 0.25:1 to 7:1.
 2. The aluminum alloy of claim 1, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy is at least 0.5.
 3. The aluminum alloy of claim 3, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy is at least 0.9.
 4. The aluminum alloys of claim 1, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy is not greater than 5.0.
 5. The aluminum alloy of claim 5, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy is not greater than 3.0.
 6. The aluminum alloy of claim 6, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy is not greater than 1.5.
 7. The aluminum alloy of claim 1 comprising not greater than 0.04 vol. % of the Fe—Mn-bearing intermetallic particles.
 8. The aluminum alloy of claim 1, wherein the aluminum alloy composition comprises one of (a) 20-500 ppm Zn, (b) 20-500 ppm Ga, or (c) 20-500 ppm Zn and 20-500 ppm Ga.
 9. A method comprising: a) forming an aluminum alloy melt, wherein the forming comprises: (i) using 20-600 ppm Fe in the melt; and (ii) using 10-800 ppm Mn in the melt, wherein: (A) a ratio of Fe (ppm)-to-Mn (ppm) in the melt is from 0.25:1 to 7:1; and b) depositing the melt to form an aluminum electrode alloy product, wherein the depositing comprises: (i) casting the melt into the aluminum electrode alloy product; and (ii) producing at least 0.005 vol. % of Fe—Mn-bearing intermetallic particles, wherein the aluminum electrode alloy product includes the at least 0.005 vol. % of the Fe—Mn-bearing intermetallic particles.
 10. The method of claim 9, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is at least 0.9.
 11. The method of claim 10, wherein the ratio of Fe (ppm)-to-Mn (ppm) in the melt is not greater than 1.5.
 12. The method of claim 11, wherein the aluminum electrode alloy product includes not greater than 0.04 vol. % of the Fe—Mn-bearing intermetallic particles.
 13. A 5xxx aluminum alloy comprising: a) 0.2-5.0 wt. % Mg; b) 20-600 ppm Fe; and c) 10-800 ppm Mn, wherein a ratio of Fe (ppm)-to-Mn (ppm) in the aluminum composition alloy is from 0.25:1 to 7:1.
 14. The 5xxx aluminum alloy composition of claim 13, wherein the aluminum alloy composition includes: 70-110 ppm Fe; 30-50 ppm Mn; wherein a ratio of Fe (ppm)-to-Mn (ppm) in the aluminum alloy composition is from 1.4:1 to 3.6:1; 90-110 ppm Zn; and 90-110 ppm Ga.
 15. The 5xxx aluminum alloy of claim 14, wherein the 5xxx aluminum alloy comprises from 0.005 to 0.04 vol. % of Fe—Mn-bearing intermetallic particles. 